UNIVERSITY   OF   CALIFORNIA        AGRICULTURAL   EXPERIMENT  STATION 
COLLEGE   OF   AGRICULTURE  BENJ>    |DE    WHEELER.    President 

BERKELEY  THOMAS    FORSYTH    HUNT,    Dean   and    Diractor 

H.     E.    VAN     NORMAN,     Vice    Director    and     Dean 
University     Farm     School 

CIRCULAR  NO.  182. 
(November,  1917.) 

EXTENDING  THE  AREA  OF  IRRIGATED  WHEAT  IN 
CALIFORNIA  FOR  1918. 

By  Frank  Adams.* 

Irrigation  has  never  been  a  large  factor  in  wheat  production  in  Cali- 
fornia. Grain  growing  as  thus  far  practiced  here  is  essentially  an 
extensive  operation  in  which  irrigation  ordinarily  has  little  part.  The 
last  census  showed  less  than  5  per  cent  of  the  wheat  acreage  of 
California  as  irrigated. 

California  cereals  are  raised  chiefly  in  three  main  valleys — Sacra- 
mento, San  Joaquin  and  Imperial.  A  personal  canvass  of  the  wheat 
situation  under  the  irrigation  projects  of  these,  and  also  of  Honey  Lake 
and  Shasta  valleys  by  members  of  our  division,  made  during  the  past 
two  weeks,  indicates  that  irrigation  can  be  made  a  decided  factor  in  the 
California  wheat  program  for  1918  if  the  farmers  under  irrigation 
projects  are  so  disposed. 

Sacramento  Valley  offers  a  large  opportunity  for  increasing  the 
irrigated  wheat  acreage  in  1918  but,  generally  speaking,  the  use  of 
water  on  this  crop  in  this  valley  has  been  proved  to  be  of  advantage 
only  in  years  of  less  than  normal  rainfall.  In  the  Durham  and  Chico 
sections  low  yields  are  even  held  by  experienced  growers  to  result  more 
from  too  much  rainfall  than  from  too  little,  the  exception  to  this  being 
the  late  spring  sowings  followed  by  deficient  seasonal  precipitation. 
Outside  of  the  upper  east  side  portions  of  the  valley,  however,  and  the 
lower  lands  near  the  river  that  are  in  some  cases  used  for  wheat,  irri- 
gation has  proved  a  distinct  advantage  when  the  rainfall  is  below 
normal,  or  is  up  to  normal  for  the  year  but  below  it  in  the  spring  when 
drying  north  winds  may  materially  check  the  yield,  unless  counteracted 
by  rain  or  irrigation.  If  1917-1918  should  be  a  dry  season  the 
production  on  100,000  acres  of  grain  land  under  the  six  principal 
irrigation  projects  of  the  valley  could  be  very  materially  increased  by 
irrigation,  but  in  many  cases  this  would  necessitate  having  enlarge- 
ments or  lateral  extensions  ready.  Of  these  100,000  acres,  30,000  acres, 
not  counting  land  in  summer  fallow,  are  idle  or  only  in  pasture  in  1917. 


•Cooperative  Irrigation  Investigations  in  California. 
33913 


—  2  — 

Assuming  that  material  extensions  will  not  be  made  on  the  basis  of 
wheat  irrigation  alone,  the  area  under  Sacramento  Valley  projects 
which  it  is  practicable  to  consider  available  for  irrigated  wheat  in  1918 
if  the  season  is  a  dry  one  is  probably  under  50,000  acres.  There  was  no 
irrigated  wheat  under  these  projects  in  1917  and  less  than  2,000  acres 
of  irrigated  barley  and  oats.  While  experiments  at  the  University 
Farm  at  Davis  have  shown  that  when  the  seasonal  moisture  is  below 
normal,  one  or  two  irrigations  will  increase  the  yield  of  wheat  very 
materially — the  increase  in  two  dry  seasons  ranged  from  265  to  440  per 
cent — the  irrigation  of  more  than  a  few  thousand  acres  of  wheat  in 
Sacramento  Valley  in  1918  is  not  likely,  except  in  a  very  dry  season  or 
through  an  active  wheat  irrigation  campaign. 

San  Joaquin  Valley,  especially  around  Tulare  Lake  and  in  Kern 
County,  grows  the  chief  area  of  California  irrigated  wheat,  the  main 
irrigation  projects  reporting  57,500  acres  in  1917  out  of  a  total  of 
260,000  acres  of  irrigated  grain  under  all  of  the  main  irrigation  projects 
of  the  valley.  While  the  northern  San  Joaquin  Valley  counties  were 
formerly  banner  wheat  producing  areas,  they  seem  no  longer  to  be  a 
large  factor  in  California  wheat  production;  and,  although  possibilities 
for  an  increase  under  irrigation  in  these  northern  counties  in  1918  are 
good,  careful  inquiry  indicates  that  only  an  active  educational  campaign 
will  bring  about  sufficient  increase  to  be  of  consequence.  North  of 
Fresno,  however,  there  are  at  least  150,000  acres  under  San  Joaquin 
Valley  irrigation  projects  on  which  wheat  can  be  grown  and  irrigated 
to  the  extent  that  the  substitution  of  irrigated  wheat  for  other  annual 
crops  is  found  wise.  Of  these  150,000  acres,  at  least  one-sixth  is  now 
idle  or  is  reported  as  not  likely  to  be  farmed  by  its  present  owners  in 
1918,  due  to  labor,  money  or  other  shortage.  Evidently,  without  a  very 
active  educational  campaign  in  the  counties  north  of  Fresno,  the  largest 
increase  in  the  San  Joaquin  Valley  irrigated  wheat  acreage  in  1918  will 
be  in  those  sections  now  giving  most  attention  to  this  crop — Kern 
County  and  the  Tulare  Lake  region.  These  sections  produced  all  but 
600  of  the  57,500  acres  of  irrigated  wheat  grown  under  the  chief  San 
Joaquin  Valley  irrigation  projects  in  1917.  Furthermore,  they  report 
over  200,000  acres  open  to  irrigated  annual  crops,  including  wheat,  in 
1918,  and  a  probable  increase  in  the  irrigated  wheat  area  next  year  of 
over  20,000  acres,  or  of  about  40  per  cent.  Unfortunately,  however,  the 
section  in  which  the  largest  increase  for  1918  is  locally  forecasted,  actual 
wheat  yields  tend  to  ebb  and  flow  with  the  floods  of  Kings  and  Kern 
rivers  as  they  rise,  and  evaporation  and  use  lower  the  level  of  the  surface 
of  Tulare  Lake.  Local  conditions — sometimes  smut,  sometimes  rust, 
sometimes  worn-out  soil — vary  the  possibilities  of  increasing  the  irrigated 


—  3  — 

acreage  of  wheat  in  this  valley,  but  even  giving  consideration  to  these, 
much  can  be  accomplished  if  the  necessity  for  it  is  brought  home  to  those 
who  are  in  a  position  to  act.  In  some  cases  those  in  charge  of  the  canal 
systems  may  be  able  to  further  the  irrigation  of  wheat  by  so  changing 
their  winter  canal-cleaning  schedules  as  to  make  more  water  available  in 
the  early  winter  for  irrigation  prior  to  seeding.  In  Madera  County  a 
low  rate  for  water  up  to  March  gives  irrigators  an  opportunity  to  flood 
grain  land  at  a  low  cost  and  such  flooding  should  ordinarily  make  the 
crop  if  later  rainfall  is  deficient. 

Increase  in  the  irrigated  wheat  acreage  in  Imperial  Valley  in  1918 
will  be  almost  entirely  a  matter  of  propaganda.  Of  401,000  crop-acres 
irrigated  in  this  valley  in  1917,  76,000  acres  were  in  barley  and  only 
1,220  acres  in  wheat.  The  area  under  the  ten  mutual  companies  of  the 
valley  stated  to  be  normally  available  for  grain  growing  under  irriga- 
tion in  1918  approximates  85,000  acres,  which  of  course  does  not  include 
in  excess  of  100,000  acres  of  land  now  in  other  annual  crops  than  grain ; 
nor  does  it  include  at  least  10,000  acres  of  undeveloped  land  under 
Mutual  Water  Company  No.  3.  Yet  without  an  active  wheat  campaign 
in  the  valley  and  in  addition,  unless  a  supply  of  satisfactory  seed  is 
made  available,  it  is  not  likely  that  the  irrigated  wheat  acreage  there  in 
1918  will  be  large.  Some  in  the  valley  are  emphatically  opposed  to 
wheat  growing  there,  previous  failures  due  to  rust  and  poor  seed  being 
fresh  in  mind.  On  the  other  hand,  a  number  of  farmers  there  believe 
in  wheat  and  the  growers  of  the  1,220  acres  of  irrigated  wheat  in  1917 
report  a  satisfactory  yield.  Furthermore,  experiments  at  the  Imperial 
Valley  experiment  station  of  the  University  of  California  show  a 
response  to  irrigation  by  wheat  exceeding  that  by  barley.  Yields  as 
high  as  35  to  57  bushels  per  acre  have  been  obtained  with  irrigated 
White  Australian  wheat  at  the  Imperial  experiment  station  and  in 
consequence  and  after  careful  observations  of  the  behavior  of  wheat 
under  irrigation  in  this  valley,  those  in  charge  have  advised  that  on  the 
better  soil  of  the  valley  wheat  is  likely  to  be  more  profitable  than  barley. 
Conditions  in  Imperial  Valley  therefore  seem  ripe  for  a  substantial 
increase  in  wheat  production  if  deemed  necessary  to  make  up  the  state 's 
allotted  quota. 

There  is  no  good  reason  why  under  a  normal  water  year,  the  entire 
increased  wheat  production  called  for  from  California  by  the  national 
program  could  not  be  produced,  if  deemed  desirable,  under  irrigation. 
Decision  No.  4278  of  the  State  Railroad  Commission  applying  to  water 
utilities  and  chapter  191,  Session  Laws  of  California,  1917,  applying  to 
mutual  water  companies,  open  the  way  for  furnishing  water  for  emer- 
gency use  on  wheat  and  other  annual  crops  where  previously  this  might 


—  4  — 

have  been  impracticable.  Availability  of  fall  or  winter  water  for  wheat 
irrigation  under  a  number  of  our  valley  projects  makes  it  possible  to 
irrigate  a  large  acreage,  and  thus  furnish  a  considerable  measure  of 
insurance  against  spring  drouth,  if  the  landowners  are  so  disposed. 
At  least  100,000  acres  of  California  land  now  lying  idle  or  nearly  so,  or 
first  to  be  ready  for  cultivation  in  1918,  will  be  open  to  irrigated  wheat 
in  1918  except  to  the  extent  that  local  conditions  not  disclosed  by  our 
survey  make  wheat  production  impracticable  or  unwise.  Some  of  this 
will  probably  not  be  farmed  in  1918  unless  purchasers  or  tenants  are 
found.  Certainly  out  of  all  the  areas  indicated,  irrigation  can  very 
effectively  aid  the  war  wheat  program  for  the  coming  year. 

Berkeley,  Cal.,  September  10,  1917. 


